PMCID: PMC1694447, DOI: 10.1128/CVI.00205-06
Although cattle develop humoral immune responses to Shiga-toxigenic (Stx+) Escherichia coli O157:H7, infections often result in long-term shedding of these human pathogenic bacteria. The objective of this study was to compare humoral and cellular immune responses to Stx+ and Stx- E. coli O157:H7. Three groups of calves were inoculated intrarumenally, twice in a 3-week interval, with different strains of E. coli: a Stx2-producing E. coli O157:H7 strain (Stx2+ O157), a Shiga toxin-negative E. coli O157:H7 strain (Stx- O157), or a nonpathogenic E. coli strain (control). Fecal shedding of Stx2+ O157 was significantly higher than that of Stx- O157 or the control. Three weeks after the second inoculation, all calves were challenged with Stx2+ O157. Following the challenge, levels of fecal shedding of Stx2+ O157 were similar in all three groups. Both groups inoculated with an O157 strain developed antibodies to O157 LPS. Calves initially inoculated with Stx- O157, but not those inoculated with Stx2+ O157, developed statistically significant lymphoproliferative responses to heat-killed Stx2+ O157. These results provide evidence that infections with STEC can suppress the development of specific cellular immune responses in cattle, a finding that will need to be addressed in designing vaccines against E. coli O157:H7 infections in cattle.
Clin Vaccine Immunol
Animals; Antibodies; Bacterial; Cattle; Cattle Diseases; Escherichia coli Infections; Escherichia coli O157; Humans; Leukocytes; Mononuclear; Lymphocyte Activation; Shiga Toxin 2
E coli O157:H7; Cows; Immune response
Hoffman, Mark A; Menge, Christian; Casey, Thomas A; Laegreid, William; Bosworth, Brad T; and Dean-Nystrom, Evelyn A, "Bovine immune response to shiga-toxigenic Escherichia coli O157:H7." (2006). Manuscripts, Articles, Book Chapters and Other Papers. 6.